'Rock Snot' discovered in the Delaware River

Extensive mats of the invasive aquatic algae, Didymosphenia geminata, also known as didymo or “Rock Snot,” were discovered in the Middle Delaware National Scenic and Recreational River within the Delaware Water Gap National Recreation Area.

The large blooms in the Delaware were originally determined to extend over a 100-mile stretch of river, from an area near the confluence of the east and west branches of the Delaware near Hancock, New York, downstream to the vicinity of the Dingmans Ferry Bridge, Pa. Additional surveys completed this week by scientists from the Delaware River Basin Commission reveal that the bloom extends much farther downstream. The algae can have negative impacts on natural and recreational resources.

On Friday, May 4 at 11 a.m., officials and scientists from the National Park Service, Delaware River Basin Commission, and Pennsylvania Fish and Boat Commission will be present at Bushkill Access, off Route 209 in Bushkill, Pa. to take part in a containment effort. Other organizations and agencies may participate.

A panel of experts will also present the latest information on the infestation of the invasive algae Didymosphenia geminata (also known as Didymo or “Rock Snot”) in the Delaware River. A question and answer session will follow the presentations. Officials will be available for interviews and a boat will escort members of the media to locations on the river where the algae can be seen. Rangers will demonstrate proper decontamination procedures.

Containment of the algae to the Delaware River is a primary objective for managing this infestation. Anglers, boaters and other river users can easily spread the algae to other waterways where it can have detrimental effects on the ecology and recreational use of those waters.